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Ultrastructure of Arterial Spasms as Related to Atherosclerosis and Hyperlipidemia

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Title: Ultrastructure of Arterial Spasms as Related to Atherosclerosis and Hyperlipidemia
Authors: Ito, Masahiro
Authors (alternative): 伊東, 正博
Issue Date: 25-Oct-1985
Citation: Acta medica Nagasakiensia. 1985, 30(1-3), p.204-224
Abstract: Morphological changes induced in contracted arteries by repeated electrical stimulation with a 3.5 volt pulse wave were examined by light and electron microscopy. The effects of mild hypercholesterolemia on contracted arteries were also investigated. Renal or femoral arteries from rabbits were stimulated over periods of time ranging from 15 minutes to 14 days. A total of 46 animals were examined. They were divided in the following three groups: (1) Electrical stimulation. (2) Electrical stimulation with a cholesterol load. (3) Control including a sham operation. In the electrical stimulation group, scanning electron microscopic examination revealed various endothelial changes such as irregularities in cell orientation, adherence of leukocytes and platelets, swelling of the marginal fold and the appearance of microvillied cells. The incidence and degree of these changes increased as the stimulation time increased. Occasionally, characteristic cytoplasmic elongations of the endothelial cells were observed. However, obvious endothelial denudation was not observed. Transmission electron microscopy revealed junctional damages and activated pynocytosis in the endothelial cells. The numbers of vacuoles observed in the medial smooth muscle cells increased rapidly after only a short period of stimulation. Medial necrosis was observed in only two cases. Fibromuscular intimal thickening, up to 3 cell layers, had formed by the 14th day of stimulation. In the group receiving both electrical stimulation and cholesterol administration, endothelial changes were generally more intense than in the former group. Emigration of monocytes through the endothelium was frequently observed. Endothelial denudation was not detected in this group either. The mean serum cholesterol value for this group was 288 mg/dl just before electrical stimulation was started. Foam cells, which were often accompanied by plasma insudation, appeared in the subendothelial spaces within the first 3 days of stimulation. Morphologically, these foam cells appeared to have originated from monocytes. Early stages of atherosclerosis were obtained within 7 to 14 days of treatment. No significant intimal thickening or foam cells were detected in the control and sham operated animals. These results suggested that endothelial changes, especially junctional damages, may be directly involved in the production of atherosclerotic lesions during angiospasm, wheres endothelial denudation might not be necessary for lesions to occur. In addition, mild hyperlipidemia enhanced the development of atherosclerosis contracted arteries, but did not appear to be an initiating factor.
URI: http://hdl.handle.net/10069/15680
ISSN: 00016055
Type: Departmental Bulletin Paper
Text Version: publisher
Appears in Collections:Volume 30, No. 1-3

Citable URI : http://hdl.handle.net/10069/15680

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